This invention is in the field of turbine engines and in particular in the field of pressurized gas driven turbine engines.
The conventional design for the turbines used in turbine engines incorporates small fins on the turbine. In order for the turbine engine to be efficient, there must be extremely close tolerances are required between the expansion chamber and the turbine fins. Also, the expansion chamber and the turbine, including the fins, must be able to withstand high temperatures. These restraints on conventional turbines makes them very expensive to manufacture. This has greatly limited the use of turbine engines in many applications.
Essentially all automobiles, trucks, buses, boats, ships, trains and smaller aircraft are powered by internal combustion engines. These engines are either spark plug ignited gasoline engines or compression heat ignited diesel engines. The efficiency of these engines, in the conversion of chemical energy to mechanical energy, is only in the rage of 20 to 25 percent. The remaining 75 to 80 percent is lost as heat in the exhaust or in the liquid cooling system through a radiator.
By comparison, the conversion of chemical energy to mechanical energy in an efficient turbine engine is approximately 45 percent. Despite the substantially higher efficiency of a turbine engine, turbine engines have not found wide application, primarily due to initial cost.
Many attempts have been made to devise an apparatus to reduce the large amount of heat which is wasted by internal combustion engines. The device disclosed in U.S. Pat. No. 4,406,127 to Dunn utilizes steam generated by injecting water onto an exhaust manifold to generate steam for powering a separate steam cylinder. Similarly, the device disclosed in U.S. Pat. No. 4,433,548 to Hallstrom utilizes steam generated by injecting water onto an exhaust manifold to provide supplemental energy to each of the cylinders.
An exhaust gas steam turbine for providing supplemental power to an automobile is disclosed in U.S. Pat. No. 4,590,766 to Striebich. For this drive unit, waste heat in the exhaust gases is utilized to produce steam for powering a supplemental turbine. A similar drive unit is disclosed in another U.S. Patent to Striebich, U.S. Pat. No. 4,785,631 and incorporates a turbine rotating element with spiral blading.
U.S. Pat. No. 4,996,845 to Kim discloses a device for utilizing waste heat from an internal combustion engine to generate steam and drive a turbine which is used for a generation of power for auxiliary use in the automobile and for heating and cooling of the passenger compartment.
U.S. Pat. No. 5,000,003 to Wicks discloses an apparatus which utilizes waste heat from an internal combustion engine to power a turbine. The inventor claims that this device has the ability to increase the overall efficiency of the engine from 25 percent to approximately 40 percent.
A hybrid internal combustion/turbine engine is disclosed in U.S. Pat. No. 5,176,000 to Dauksis. For this device, an internal combustion engine is utilized to generate heat for the production of steam which is used to power a turbine. The turbine is then utilized to drive an electric generator to charge batteries which are used as a complimentary or alternate source of propulsion for a ground vehicle.
The apparent lack of commercial success for any of the foregoing inventions is probably attributable primarily to cost. The additional cost cannot be amortized, over the lifetime of the vehicle by the fuel cost savings. The result of the foregoing is that, as consumers, we have elected to live with the low efficiency and environmental problems associated with internal combustion engines. However, the extent of the effort made to attempt to deal with the efficiency and environmental problems, as manifest by the foregoing prior art, demonstrates the extent of the need for a high efficiency engine for these applications.
The high cost of turbine engines is primarily the consequence of the close tolerance required for the construction of the turbine and the turbine body and the very high cost of materials required for heat tolerance and durability required for the traditional turbines. Particularly, the turbine fins and the turbine seat in the turbine body must be machined to very close tolerance of highly durable material. Otherwise, high efficiency will not be achieved and wear and loss of efficiency will be excessive.
The device disclosed in U.S. Pat. No. 4,883,404 to Sherman provides for the passage of fluids through a turbine for use in cooling the turbine.
The present invention utilizes steam or other pressurized gas which is directed from the center of the turbine to nozzles at the perimeter of the turbine. The nozzles have a gas discharge which is oblique to the direction of rotation of the turbine.
The present invention may also be utilized with a geothermal well, with the heated water being passed directly to the nozzles where the water is flashed to steam as the water is passed through the nozzles. Conventional geothermal generator facilities require the flashing of hot water extracted from the geothermal well to steam, and the steam is then passed to the turbine. This results in a substantial loss of energy from the water in converting it to steam. The direct flashing of the hot water in the nozzles of the present invention increases the efficiency substantially. This advantage of the present invention can be used for other applications as well, to increase efficiency and decrease complexity.
An objective of the present invention is to provide a turbine for a high efficiency engine which is economical enough for automobile and other small engine applications.
A further objective of the present invention is to provide a high efficiency turbine engine which is economical enough for automobile and other small engine applications.
A further objective of the present invention is to provide a high efficiency turbine engine for which the need for close tolerance machining and the need for high cost parts and materials are greatly reduced.
A further objective of the present invention is to provide a turbine engine which can utilize fuel types other than gasoline or diesel.
A further objective of the present invention is to provide a turbine engine which does not require the burning of fossil fuel at high pressure, thereby lessening the amount of oxide type air pollutants.
A further objective of the present invention is to provide a turbine engine that can be used with electric motor driven or partially electric motor driven vehicles which utilize battery storage of energy.
A further objective of the present invention is to provide a turbine engine that provides for the direct flashing of heated water to steam gas nozzles which power the turbine.
Preferred embodiments of the turbine engine of the present invention comprise a turbine, a turbine shaft, a turbine body and turbine shaft bearings. For these embodiments the turbine has at least two gas nozzles which are hydraulically connected by nozzle gas ways to internal shaft gas ways in the turbine shaft. For these embodiments, the turbine shaft is hollow or tubular with one or more internal shaft gas ways.
The turbine is contained within the turbine chamber of the turbine body. The turbine seat is dimensioned to be proximal to the perimeter of the turbine, thereby inducing a ground effect for gas exiting the nozzles. The close tolerance between the gas exits and the turbine seat peripheral surface is the only aspect of the turbine body that requires accurate machining. Unlike a conventional turbine, the front face of the turbine does not need to closely fit the front wall of the turbine chamber. The turbine nozzles, the turbine seat peripheral surface, the shaft gas ways and the nozzle gas ways are the only components of the turbine engine that experience very high temperatures.
For preferred embodiments, to provide for inertial balance of the turbine, if there is only one gas shaft way, the internal gas shaft way is circular and annular centered in the turbine shaft, and the gas nozzles are equally spaced at nozzle locations around the perimeter of the turbine. The nozzle angle between the axis of the gas exit nozzles and the direction of rotation of the perimeter of the turbine at the nozzle locations is also uniform.
Certain preferred embodiments utilize multiple shaft gas ways with each shaft gas way linked to one or more opposing pairs or equally spaced groups of coordinated gas nozzles, thereby providing for balance of the torque applied to turbine. Each shaft gas way may be connected to an independently controlled steam flash generator or other pressurized gas source, providing for independent activation, deactivation and gas feed for each pair of gas nozzles connected to the shaft gas way. This provides for increasing and decreasing the power supplied to the turbine while maintaining the pressure and the rate of gas flow at each gas nozzle within a desired range.
The nozzle angle is oblique to the direction of rotation of the perimeter of the turbine. Lesser nozzle angles increases the ground effect but decreases the efficiency of the direct momentum transfer of the exiting gas to the turbine, while greater nozzle angles increase the direct momentum transfer while decreasing the ground effect.
Pressurized gas is routed from a gas source through a shaft gas connector to the turbine shaft gas ways. The gas passes through the turbine shaft gas ways to the shaft gas distributor which directs the gas from each of the turbine shaft gas ways to the respective connected nozzles through the nozzle gas ways.
For certain preferred embodiments, as the pressurized gas is discharged from the gas exit nozzles in a direction opposite the desired direction of rotation of the turbine, it is also discharged against the turbine seat annular peripheral surface. This produces a back force that creates the ground effect, thereby increasing the efficiency of the engine. Other embodiments do not utilize a ground effect.
Some preferred embodiments incorporate a gas exit cone on each nozzle to enhance the efficiency of the turbine engine. The gas exit cones can be recessed in the perimeter of the turbine or affixed to the perimeter of the turbine by nozzle support tubes.
For embodiments of the present invention using steam to power the turbine, steam generators have steam chambers with controlled outputs. These outputs are controlled by a control valve, which are monitored and controlled by a steam control computer. For preferred embodiments the steam generators will be flash steam generators. The flash chambers for flash steam generators will be quite small in relation to the heat source, thereby providing for a quick recovery. A pressure sensor is used by the steam control computer to monitor the steam pressure in the flash chamber. The control computer allows the pressure in the flash chamber to reach a desired pressure and maintains the pressure at that level. When the need for more steam is determined by the control computer, the control valve is opened for that flash chamber. If more steam is required, more control valves are opened, bringing more flash chambers on line. As the steam pressure in the flash chamber is depleted, the control computer determines that more water is required and increases the water flow. Other embodiments may incorporate a combination of flash generators and other types of steam generators. This can provide for a fixed amount of steam at a constant rate while leaving the flash generators for quick response to special power demands for the turbine. Other embodiments may utilize only a fixed steam system. For these embodiments, the rotation speed or the amount of power that is delivered to the turbine is still controlled by a series of valves which are controlled by the control computer. This type of steam generator may be more readily adapted to an engine used to generate electric power for battery storage for use with an electric motor driven device.
The control computer continually monitors and controls the operating parameters of the turbine engine through use of sensors, feed back controls, and output devices. Turbine speed, required torque, gas or steam pressure, turbine balance and direction of rotation of the turbine are some of the parameters that are monitored and controlled. The control computer also controls water levels, water temperature, and water flow for cooling in a steam system and air flow around the expansion chamber for pressurized gas. By controlling water flow, the control computer can maximize the efficiency of the engine.
For other preferred embodiments of the pressurized gas turbine engine, pressurized gas may be supplied through an engine gas port in the front wall of the turbine engine. A preferred embodiment of the turbine engine with the front wall of the turbine engine removed. A turbine seal ring is affixed to the front face of the turbine and provides a gas seal between the front face of the turbine and the front wall of the turbine engine, thereby creating a gas supply zone between the front face of the turbine and the front wall of the turbine engine which is bounded by the gas seal. This provides for pressurized gas to be directed from the engine gas port to the turbine gas port. For some embodiments, the turbine seal ring is not centered on the axis of the turbine. This provides for the more uniform distribution of seal oil for all points of contact between the turbine seal and the front wall of the turbine engine. The seal oil enhances the ability of the turbine seal to minimize pressurized gas leakage between the turbine seal and the front wall of the turbine engine. The seal oil is typically injected into the contact zone between the turbine seal and the turbine engine front wall through a seal oil injector port in the front wall of the turbine engine.
For some embodiments, the nozzle gas ways are machined, formed or cast in the turbine and sealed by the turbine front face plate. The nozzles are installed in a nozzle recess in the turbine perimeter. The nozzle recesses provide for the tip of each of the nozzles to be inside the turbine perimeter, thereby providing for streamlining the turbine perimeter and allowing for a closer tolerance between the turbine perimeter and the turbine seat peripheral surface.
The turbine engine may have a turbine seat peripheral surface with transverse serrations which increase the ground effect experienced by the turbine as pressurized gas is discharged through the nozzles. A spent gas evacuator may be attached to the turbine or the turbine may have an evacuator spindle extending from the rear face with the spent gas evacuator anchored to the evacuator spindle. The transverse serrations typically will extend also to the gas expansion area of the turbine seat which is proximal to the perimeter of the spent gas evacuator. For these embodiments, the rear face of the spent gas evacuator is proximal to the turbine engine rear wall. The expansion chamber is occupied by the spent gas evacuator and the spent gas is directed to a spent gas evacuation channel for discharge through a spent gas port.
A nozzle or one or more opposing pairs or equally spaced groups of coordinated nozzles may be connected to separate pressurized gas sources through the use of multiple turbine gas seals and turbine gas ports which direct the pressurized gas received through respective engine gas ports in the front wall of the turbine engine and respective gas supply zones between the front face of the turbine and the front wall of the turbine engine, to respective nozzle gas ways and thus to the respective nozzle or pairs or groups of coordinated nozzles. Another embodiment which provides for two separate gas sources to be utilized with pairs or groups of coordinated nozzles utilizes a central internal shaft gas way to transmit gas from one pressurized gas source through interconnected nozzle gas ways to a first group of coordinated nozzles, and utilizes the annular space between the shaft gas way and the inside surface of the shaft tube of the turbine shaft as a second shaft gas way to transmit gas from a second pressurized gas source through other interconnected nozzle gas ways to a second group of coordinated nozzles.
The present invention can also be used with simplified, high efficiency systems by providing for the direct flashing of hot water to steam in the nozzles. This has use for a number of applications such a geothermal wells. This avoids the high energy losses which occur as hot water is flashed to steam and the steam is used to power the turbine.